Toxoplasmosis is a parasitic disease, the agent of which is an opportunistic intracellular protozoan, Toxoplasma gondii. Clinical signs of the disease in immunocompetent persons are rare. However, toxoplasmosis is increasingly associated in these persons with lymphadenopathies, fevers, neurological signs (decrease in the intelligence quotient, reduction of psychomotor performances), ocular lesions, severe disseminated infections and even neurological or psychiatric lesions such as schizophrenia. In immunodepressed patients (for example AIDS, grafted, patients having haematological problems) or in the fetus, Toxoplasma gondii appears as an opportunistic pathogen which may cause severe lesions.
During its parasitic cycle, Toxoplasma gondii may appear in three different forms: a tachyzoite form, a bradyzoite form and an oocyte form. The chronic form of the disease is due to the bradyzoite form, contained in intracellular cysts (5 to 70 μm) notably localized in nerve and muscle cells. The cysts persist in these tissues until death of the host. The host-parasite immune equilibrium allows them to be kept quiescent. These forms are very resistant and may survive several days at room temperature.
A certain number of molecules (for example pyrimethamine, sulfadiazine and sulfadoxine) are present on the market. However, these molecules have an effect against the tachyzoite primary form of the disease. Indeed, presently there is no treatment against chronic toxoplasmosis, no drug to this day being capable of removing the tissue cysts. The only known molecule has a cysticidal effect in vitro is atovaquone (U.S. Pat. No. 5,641,769), the cysticidal activity of this molecule in vivo having never been demonstrated.
Toxoplasma gondii belongs to the phylum of Apicomplexes (branch Apicomplexa) which groups a large number of parasites responsible for diseases such as malaria, neosporosis, coccidiosis and cryptosporidiosis. With research work aiming at identifying new anti-parasite active ingredients, it was possible to identify apicidin, acyclic tetrapeptide extracted from the fungus Fusarium pallidoroseum. Apicidine has some effectiveness in vivo on mice infected by the malaria of Plasmodium berghei (Darkin-Rattray et al. Proc. Natl. Acad. Sci. USA 1996; Singh et al., Tetrahedron Lett. 1996). This molecule would have an inhibitory action on histone deacetylase (HDAC) of Plasmodium berghei. 
There exist different forms of HDAC. The inhibitors of HDAC represent a class of more than 8,000 compounds. Today, they are the subject of research and development, for example as anticancer agents or as effective and selective immunosuppressive agents in humans. The class of the HDAC inhibitors notably comprises cyclic natural derivatives of the peptide type having shown some effectiveness. Among the latter, mention may be made of chlamydocin, isolated from the fungus Diheterospora chlamydosporia and which has demonstrated an anticancer activity in vitro, and derivatives of chlamydocin, isolated from the fungus Peniophora sp. and which cause interruption of the cell cycle in plants (Tani et al. Phytochem. 2003).
A certain number of drawbacks are associated with the use of the compounds with a human therapeutic target, which are derived from biological material such as notably apicidin and chlamydocin. Notably, it is impossible to control the exact composition of the extract, for example the presence of associated molecules potentially having an uncontrolled biological effect. Further, the problem is posed of the accessibility of said material. The problem of the cost for preparing the active compound is also posed.
Nishino et al. (Nishino et al., Bioorg. Med. Chem, 2004) propose several chemical syntheses of derivatives of chlamydocin. Each synthesis involves several reactions. In order to obtain a derivative, each synthesis applies a different synthesis approach, so that the proposed syntheses do not have much flexibility.